How to change only the hair colour in a video without tinting the skin
Ask Vizard Agent for the new hair colour and say nothing else may change. It tracks the hair through the clip, changes only the colour of those pixels while their brightness stays exactly as filmed, keeps skin out where hands or a forehead cross the hair, and measures the face and background afterwards to prove they didn't move.
What do you type into Vizard Agent?
Name the colour and say that the face, skin and clothes must stay exactly as filmed. A word like softer works well for adjusting strength afterwards. Mention it if hands touch the hair in the clip, because skin that crosses the hair is where colour most often spills.
Change only the hair colour to purple. Keep the face, skin, clothes, background and lighting exactly as they are.
What does Vizard Agent actually do?
It changes colour without touching brightness, because brightness carries the strands, the shine and the shadows that make hair look real. Keeping it identical is also what stops the edit looking painted on. In the two sessions behind this article it:
- Tracked a hair matte through each clip and changed only the colour channels inside it. The brightness channel stayed bit-identical in all 1,346 frames of one clip.
- Found purple on a hand and a comb crossing the hair, measured the hair's own colour, and added a skin gate tuned so that dark strands still passed.
- Baked the per-pixel rules into a colour lookup table when the first version rendered at about two frames a second, so a 30-second test then took 34 seconds.
- Measured areas that should not change and found the cheek shifted from RGB 145,102,92 to 153,106,92 by a colour conversion outside the matte. After the fix, the cheek moved by less than one level on average.
- Re-timed the matte to the phone clip's irregular frame timing, and made "softer" a 65/35 blend with the original, reusing the same matte.
When does this not work well?
When the new colour is much lighter than the hair, such as black hair to blonde or pastel lavender. Keeping the brightness is what makes the result look real, so lifting near-black hair several shades needs a generated redraw instead, which risks changing the face and leaving a visible line at the hairline.
Common questions
Can black hair go blonde? Not cleanly. Vizard Agent keeps the hair's own brightness.
Will my skin change colour? No. Vizard Agent keeps skin out of the hair matte.
Can I make it subtler? Yes. Vizard Agent blends the new colour with the original.